Quantitative Detection of Corroded Reinforced Concrete of Different Sizes Based on SMFL

In order to solve the problem of quantitative detection of corroded reinforced concrete of different sizes, the quantitative detection experiment based on spontaneous magnetic flux leakage (SMFL) was carried out in batches. Electrochemical corrosion of 27 reinforced concrete specimens was carried out, and the SMFL signals of reinforcement were obtained by magnetic detection equipment. Four-dimensional magnetic indicators M 1 – M 4 that can characterize the corrosion degree of the specimens were defined. The influence of different sizes on the magnetic indicators were analyzed. It is concluded that the thicknesses of the concrete covers affect the magnetic indicators by affecting the lift-off heights z. The influence of diameter of the rebars on the quantitative detection can be eliminated by describing the corrosion degree with the average cross-section loss rate α . The influence of length of the rebars on quantitative detection is not clear yet. Finally, Support Vector Machine (SVM) was introduced to establish a classification model of corrosion classes and magnetic indicators. Using the model to predict the corrosion classes of the specimens can achieve a high classification accuracy. The research provides a new method for the quantitative detection of steel corrosion.